Portable tangent screen



NOV 27, 1951 R. l. PRmKlN 2,576,358

PORTABLE TANGENT SCREEN Filed Nov. 4, 1949 n INVENTOR.

Patented Nov. 27, 1951 UNITED STATES PATENT OFFICE PORTABLE TANGENT SCREEN Roland I. Pri'tikin, Rockford, Ill. l Application November 4, 1949, serial No. 125,476

" 1 claim.l (o1. 88420)' This invention relates to a device for the measurement and recording of the central portion of the visual eld ofthe human eye. In more particular it is directed to an apparatus and method whereby an examining physician may chart with facility the center of the peripheral fields ofv e vision with respect to both form and color.

Devices of the prior art which have heretofore been designed to accomplish analogous'purposes usually have necessitated the use of complex, expensive and permanent or non-portable installations. By my invention the inherent disadvantages of utilizing only heavy and intricate equipment of that type are obviated, since my device comprises an entirely portable unit, designed for hand manipulation, and one which can be easily disassembled for carrying in a suitable medical kit or for shipment.

It is therefore an object of my invention to provide a device of the described nature which is extremely simple in construction and operation and which may be fabricated at an extremely low cost.

It is a further object of the invention to provide an apparatus which will enable a quick and accurate measurement by the examiningA physician, and which also permits transfer into permanent record form, with great ease, the data recorded by the physician during examination of the patient.

It is another object of my invention to enable the use of a' tangential screen which can 'be so easily disassembled and reassembled that it may be conveniently carried by the examining physician to the patients bedside. This is extremely important where it is necessary to conduct ocular examinations of non-ambulatory patients who could not be brought to the locality of a permanently installed and complex optometrical examining instrument.

Reference is now made to a more particular description of my invention, wherein the accompanying drawings illustrate one embodiment thereof devised for the practical application of the principles enumerated 'in the foregoing and ln which: v y

Figure lis a perspective view of the apparatus embodying this invention, 1 Y

` Figure 2 is a broken side view ofthe apparatus illustrated in Figurel.

FigureB is a hand target used in conjunction y with the apparatus of Figure 1.

Figure 4 is a partial side view of the device of Figure 3. e, A'

Figure 5 is another embodiment of the v`device ofFigure3,and v,

Figure 6 isa top plan view illustrating the use of the invention bya patient. l l

lReference is now made to the drawings in which like numerals indicate like parts throughout the several views. y

A- support member I has aixed to it a handle 2, intermediate the ends of the said support. The handle can, be secured for ease of disassembling merely by the use of a threaded element 3 adapted for insertion in a threaded aperture in the member I. l e

At one end of the support I is mounted an eye piece. which consists of a vertical element 4 attached in acommon manner such as by the use of a threaded terminal end 5 through insertion through an appropriate opening in `member I, at one yend thereof, and designed to receive a nut 6 for retention of the eyepiece in place. The vertical -element 4 is provided with a slanted plate or eye piece l, curved as shown for positioning on the cheek underneath the patients eye. This plate member may also be suitably allixed to the vertical support 4 by a counter-sunk screw 8.

Theopposite end of the member I is bent right angularly to the said member to also vform an upstanding support I0. The latter is designed to accommodate the sighting screen I5. The screen may be made of aluminum or any other light weight material, although, as will be shown, if the apparatus of Figure 5 is utilized subject to the influence of magnetic eld, a material such as iron or steel is necessary. Normally, all elements ofthe apparatus thus far described are painted or otherwise colored a dull black. This is true especially of theface of the screen I5, which is marked olf in certain scaled graduations enabling charting of the patients eld of vision. For'instance, a number of concentric circles I6 are intersected by radial markings I'I emanating from the center of the screen. Hence, the screen, by the scaled .graduations of I6 and I1, is divided into denite predetermined areas facilitating the accurate positioning of the tangential target as well as` the recording of sight with respect to such. target. The screen I5 is also pro vided with opposite elliptical markings I8 located on each side of the screen center. These, as will hereinafter be.l described, represent the areas within which will fall the normal blind spot of the human eye.

It is essential that this screen be mounted on its complementary support I0 in a secure manner so that whenin use it will not be displaced with respectto `the other elements hereinbefore described. particularly the eye piece. To this end e the screen is apertured at its exact center for the reception of a threaded bolt 20. The latter is provided with a relatively large and flatsurfaced head 2I, the outer face of which is marked with two lines intersecting at right angles, the point of intersection representing the exact center of the screen I5. A wing nut 24, utilized to draw the elements ID and I together and maintain them v.in `the desired position, facilitates a .breakdown by hand of the @pants just described. In order to further assure the secure positioning of screen I5 to prevent any movement after assembling, and to prevent rotation of blt 20 during rotation of the aforesaid fling nut, 'the head of the bolt is also provided with two opposite projections 23 which are adapted for `Ainsertion in complementary holes the A{scr-een :as indicated in Figure 2. As a further means .as-v suring stability of the screen I5 after it has been' mounted in the manner shown and described, an :element '26 in A'fori-r1 of a projection of the .in-ner side of support I0 is positioned fto receive fa U- Ashaped channel 25 on the center line of gthe 'bot- 'tom edge Io'f-the screen. Y

It will thus be seen that in lpositioning the screen the a-foresaiidchannel is firs't slipped over Vthe projection, the boltll is inserited vSthro'ugl'fi both screen and vsupport 2H) --With the projection 'iitted as described andthe M`Wing nut'tigiftened `to force these 'several mem-bers together.

In using my invention it is necessary --to pro- `vide Asome form 4'of tangential vltarget 'fas fdistinguished VAfrom the direct target comprising Ithe exact lcenter of screen Il5, :represented by 'the Iin'terse'cting lines on the lboltlie'ad 2 I. l'Ilii-s may V take the ferm v01 the 'hand manipulated .target of Figures 3 and 4, consisting loifa fred 33 fupon which has been mounted a fsuitable handle "dit, 'The opposite end of the rod is slotted asiat Cil 4 hand in an obvious manner, placing the eye piece immediately underneath the eye to be examined. The opposite eye is of course occluded by any opaque object, 50. n The patient focuses his direct vision upon the center marking of the bolthead 2I, as indicated by the dotted line A. The tangential or side vision is then represented .bythe .dotted-line B, the latter .being directed to fthe meint of location of the'tangential target 33. The test target, either white or colored,

` Ymay thus be moved along the various concen- A'forthe reception 1of 'a disc133. This-discisprovided with a small extension '3i lo'f `Vsuol-i thi'clcness that it may lbe rfrictiona'lly-grippe'd within the slot k"312, thereby 'being maintained -inlthe fd'esired position. 'The 'said .disc 533 also liras :a small depression llili @at its midpoint, :su'fcent to gre.- ceive wax `or paint or other suitable substances in 1any one of a :number of `[desired colors. In ypractice it is fusual f'to prov-ide -with member :Sil a number of such idi'scs 7.33 and fordinarily, in `addition to one fdisc having 'a White fcenter, -individual discs Shaving :center-s of the .primary 'colors areutilized ingorder .totestimate tangen-V tial -visien Vwith respect to color. These :discs are :obviously interchangeable, in :member isn, :at the desire of `the examining physician. :Such discs may ibe made vin zthe :alternative norm of Figure 5 iwlherein such-elements 'Ml :are eprovided ivith the `described :coloring ime'dia :42 nhere shown ialso iitted Ywith 1a Vsmall handle AI.. In this modification the idisc fis attached .by :fairy common method to a'imagnetized :element 43,@ which lwill 'then obviously adhere, :by .frmaignetisirn,

to the face of the targetiscreenst .when .placed thereon atsany -'desiredposition In @the use :fof this variation, aist'eel oriron screen fr ofcourse essential. fThus, lin both ELinstar-loes -t-he*tan'gen tial target, -either ithat of Figures 3 .ande @or that of Figure 5, yis a simple `hand-manipulated lob;

'ject which 'is placed at dinerent `points -lupcn the screen to gain the reaction thereto lwith respect tothe sci-called side vision 'rif ithe wpatient. 4From the lforegoing, the `following description of the manner of use `rof -rny invention should "be apparent. The eye testing operation'-lis more particularly illustrated in Figure -6 wherein the patient Ais shown Iholding Athevs'creen with one tric and radial meridians to make an accurate detern'nation of the extent and limits of the central .visual eld, both for form and color.

' As stated, the oval areas I8 represent the nor- Ymal physiological I blind spots. They are on each side of the screen center to enable the physician to determine visual characteristics of both the right and left eyes, as vwill be obvious.

As will be understood E-by those skilled yin 'the Iart, `the 'central 'vision is'made possible by that portion of the "retina called-the macula, which is in the very center ofl the retina. 11n all -1in dividuals `the retinahas .an Yarea -of blindness in Ithefiield -of vvision which `is known fas'the normal `'blind lspot. These 'normal blind spots in most individuals can -be ascertained byfplacfing the` target screen Witliin'the "areas Iii! land de'ternfiin'i-n'g the `visual response of ,the patient thereto. Abnormal and 'physiologicalblind vspots are also. known. These 'would orfiinarily- "be present when the ntarget vscreen fischarted in-a-n area Without the elliptical circles I8.

Hence, -by imoving either the hand v'element '3B or `the magnetzed unit 'd0 'todifejrent posi# tions upon the screen 15, `and marking-those locations on the screen Where different-,reactions of the patient take place with vrespect :to 'the tangential target, the entire central side -'v'is'ion or the center of the peripheral leld fof vision both for form and color can be readily ascertained.

In practical `use as the tangential target :'33 ismoved ,to different positions on the screen I5 these ypositions `are noted in chalk vrby `'the'ex amining physician upon the latter. Such'rna'rlings are then transferred toa paper replica of the intersecting vrlinear `markings o f the 'metal screen I5. In this Way a .permanent record .of any `visional .examination `of this `Asort iis `easily obtained. ,Y

1t will Athus be ,seen .that ,I v have provided a simple tand .inexpensive .dei/ice, Awhich may conveniently be disassembled and rearranged finto a .compact (package, and carried kto the bedside of .a patient. It enables 1not only -an .accurate and rapid testing or the .central eld ,of vision, butac'ili'tates permanent recording y off fthe IStime for future reference.

V,I claim: 1

A portable and collapsible ophthalrnological eye testing .device comprising Aa `Supiiort' member, rahand support 'element i;emovably v'mounted on said member, said `member provided 'Withrgan ancularly extendinsand removable sveipegceiat one end thereof, a 'screen .support mernber lprovided with a threaded aperture 'extending Aright angularly from saidmember at *the opposite en cl thereof, a rigid, black, markable screen,A vsaid uring tangential vision on said screen compris- 5 ing a tangential target to be superimposed upon said screen in various positions, said tangentialV target comprising a circular disc provided with a projection for hand manipulation, said disc having magnetic means mounted upon one side thereof, said disc having a colored center marking on the opposite side thereof, whereby said disc may be positioned upon said screen and maintained in fixed position thereon by said magnetic means.

ROLAND I. PRITIKIN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS FOREIGN PATETS Number Country Date 113,641 Great Britain Feb. 25, 1918 337,788 Great Britain Nov. 7, 1930 OTHER REFERENCES The B. & L. One Meter Tangent Screen Equipment, published 1934, pages f'and 11. (Copy in Division 7.)

Peter; Text; Principles of,.,Perimetry and Practice, pages 80 to 83 and 8811938), published by Lea & Febiger, PhiladelphiaLyPa. (Copy in Congressional Library.)

Poser, publication, "The Perimeter, from the Optical Journal Review, January 1, 1945, pages 23, 24 and 38. (Copy in Divisin 7.) 

